(19)
(11) EP 2 442 352 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
19.09.2012 Bulletin 2012/38

(43) Date of publication A2:
18.04.2012 Bulletin 2012/16

(21) Application number: 11184566.5

(22) Date of filing: 11.10.2011
(51) International Patent Classification (IPC): 
H01J 61/36(2006.01)
H01J 61/82(2006.01)
 H01J 61/34(2006.01)
H01J 9/32(2006.01)
(84) Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME

(30) Priority: 14.10.2010 JP 2010231066

(71) Applicant: Koito Manufacturing Co., Ltd.
Tokyo 108-8711 (JP)

(72) Inventors:
  • Homma, Akira
    Shizuoka 424-8764 (JP)
  • Harazaki, Masato
    Shizuoka 424-8764 (JP)

(74) Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser 
Leopoldstrasse 4
80802 München
80802 München (DE)

   


(54) Arc tube for discharge bulb and discharge bulb including the same


(57) An arc tube for a discharge bulb includes: an electrode assembly that has an electrode bar (22) and a molybdenum foil (24), wherein an overlapping portion of an end portion of the electrode bar (22) and a molybdenum foil (24) is joined by spot welding; a pinch seal portion (12) that seals a part of the electrode assembly, the part including at least the molybdenum foil (24); and a closed glass bulb, into which a tip of the electrode bar (22) protrudes, the closed glass bulb forming a discharge light-emitting portion, wherein the size of a recess (40), which is a weld mark, in the molybdenum foil (24) on the side opposite to a joint portion, at which the molybdenum foil (24) and the electrode bar (22) are joined with each other, is within a range from 0.07 mm2 to 0.25 mm2.







Search report









Search report